[Typo3-dev] char <-> string -> overhead -> speed

[Peter Russ]

Michael Johnston wrote:
> Unfortunately, there is only one way to optimize effectively. That is to 
> profile production code & find the slow parts then use theory, 
> intuition, but mostly trial and error to make the slow parts less slow.
> 
> Tests like the one you wrote are far too simplistic to be useful at all. 
> Want proof? Run it this way:
> 
> <?php
> $imax=5000000;
> $tStart=time();
> $nl = "\n";
> $bob = 'mary';
> for($i=0;$i<$imax;$i++) $stringString="TextTextTextText\nnewLine$bob$bob";
> $endTime=time()-$tStart;
> echo "string=$endTime.<br>";
> $tStart=time();
> for($i=0;$i<$imax;$i++) 
> $stringChar='TextTextTextText'.$nl.'newLine'.$bob.$bob;
> $endTime=time()-$tStart;
> echo "chr=$endTime.<br>";
> ?>
> 
> ....oops! now string takes longer. Why? probably because it's 
> interpolation of variables that is time consuming, not interpolation of 
> escaped characters.
> 
> If you're going to write tests to get an idea of how to pre-optimize 
> your code, you'd better write lots of different tests, or you may 
> accidentally come up with such a misleading result that you end up 
> DE-optimizing your code.
> 
> In our case, on a site with many custom content elements & plugins, we 
> quickly changed a bunch of interpolated strings that were in loops to be 
> non-interpolated and got a nice increase in speed. As measured by 
> profiling the actual site on the actual machine, before and after.
> 
> Cheers,
> Michael Johnston
> Planetactive
Thanks for your reply.
The main intention for that question was NOT to start a discussion about 
BENCHMARKING. Sorry if that was not that clear!

The question raised when I used the extdeveval extension with the option 
of transfering all " to '. Because a "\n"!='\n'.
So there should be a benefit to transfer all strings to char-arrays. For 
Java I know that is might outperform a string. But for PHP I had no 
indication that there is a benefit. But perhaps I'm missing some 
articles/source about PHP optimization.

So how would this perform "TextTextTextText\n".$bob.$bob ?
I'm interested in the advantages of doing/programming things in one way 
   or another. Any hint is highly appricated.

Regs. Peter.